Saturn: Blue Sapphire helps bring balanced detachment, calm, practicality, and endurance. When weak or afflicted, it brings troubles, weakness, disease, vulnerability or anxiety. It can cause financial hardship, lack of drive, or insomnia. A difficult Saturn may cause manifestations similar to a weak Jupiter, Sun or Mars. Blue Sapphire should be used with great caution, unless in a navaratna, and even then the size and purity should be watched. It may cause problems for thin people, those having dry skin, or those remote from the world or already overly detached (Vata). It is a difficult planet for most, but is especially favorable for Capricorn, Aquarius, Taurus and Libra Ascendants.
Rahu: Hessonite Garnet is the gem for the shadowy planet Rahu, called the North Node in the West. In this age of media, electronic devices and electromagnetic radiation, Rahu is very much affecting the world in general. It helps to balance the influences of media like television, it aids a sense of clarity, of knowing one’s own mind, and general popularity in society. When weak or poorly placed, it causes strange reactions, imaginings, occult influences, fear, agitation, addictive behavior, drugs, lack of sense of self, lack of regard for society’s norms or dissipation. Therefore, Hessonite Garnet, also known in ancient India as cinnabar, is obviously a very good gem to wear in a Navaratna during this age.
Ketu: Chrysoberyl Cat’s Eye is the gem of Ketu, called the South Node in the West. When weak, it causes doubt, uncertainty, poor discrimination, poor concentration or lack of insight. It is the planet of ultimate spiritual awakening. It causes tendencies that appear to be like a weak Ascendant. But as a weak Rahu brings lack of clarity and a clouding of perception, a weak Ketu brings doubt and questioning. The gem should be used with caution if the person is high in Pitta, as under the description for Mars, or if Ketu is in a sign of a planet that is weak or afflicted. However, if included in a Navaratna, this should be resolved by balancing both Ketu and the planet ruling the sign it falls under.